Reichling said the 19 firefighters were found in an area that also had 19 fire shelters deployed. Some of them were found inside their shelters, which are tent-like structures meant to shield firefighters from flames and heat. They are typically used as a last resort.

"The entire fire department, the entire area, the entire state is being devestated by the magnitude of this incident," Prescott Fire Chief Dan Fraijo said in a news conference. "We just lost 19 of some of the finest people you'll ever meet."

Fraijo said it is still unclear what caused the incident and he did not wish to speculate without more information.

"My heart weeps for those who lost their lives and were affected by today's Yarnell Hill Fire,'' said U.S. Rep. Paul Gosar, R-Ariz.

The lost firefighters were members of a "hotshot" crew, who specialize in attacking wildfires like the Yarnell Hill Fire. The elite firefighters often hike for miles into the wilderness with chain saws and backpacks filled with heavy gear to build lines of protection between people and fires. They remove brush, trees and anything that might burn in the direction of homes and cities.

Fraijo called these hotshot crews, "the core of firefighting. They're right there in the middle of the incident," he said.

Earlier Sunday, the wildfire prompted evacuations of 50 homes in several communities about 85 miles northwest of Phoenix. Later Sunday afternoon, the Yavapai County Sheriff's office expanded the evacuations to include more residents.

Officials at the scene of the blaze said they expect about half of the town's 500 homes to be destroyed by the fire. It has burned more than 2,000 acres and is uncontained, fire officials said.

Reichling said federal firefighting help is on the way and that the number of firefighters on the scene will reach 400.

Wickenburg Community Hospital is expecting to treat about eight firefighters who were among about 22 injured battling the fast-moving, 2,000-acre Yarnell Hill Fire that has burned through have the town, officials said Sunday evening.

The spokeswoman for Wickenburg hospital, Roxie Glover, said there are reports of as many as 22 firefighters being injured. About eight from that group were headed to the Wickenberg facility, some were being air lifted to a Phoenix burn unit and others were being transported to Yavapai Regional Medical Center, Glover said.

Jim Tavary, CEO of Wickenburg hospital, said his facility was put on alert to expect several injured firefighters but did not know their conditions or the extent of their injuries.

"We are setting up an incident command," Tavary said.

It's unclear if any in this missing group is among the dead firefighters.

Homes have burned and hospitals have reported injuries from the blaze that had reached Yarnell.

The wind-whipped blaze also prompted officials to shut 25 miles of State Route 89 between Congress and Kirkland, but residents of the hundreds of evacuated homes could still travel the estimated 30 miles to a shelter in Prescott, Reichling said.

The Yarnell Hill Fire, ignited at about 5:30 p.m. Friday, was moving north and east at the rate of about half a mile per hour, fire officials said.

As about 250 firefighters fought to keep the blaze at bay Sunday, officials evacuated three subdivisions outside Yarnell, officials said.

Speaker of the state House Andy Tobin, R-Paulden, was shaken Sunday evening during a brief interview with The Arizona Republic. He could not confirm details of the number of people injured, and said the Department of Safety was on its way to take him to the scene.

"I'm going to the scene, I'm going there," he said, adding he just spoke with his friend, Yavapai County Sheriff's Officer Scott Mascher. "The fire took an incredibly swift turn is all he (Mascher) said and he said it is very, very bad. Tonight, we need all of Arizona's prayers."

About 14 Yarnell-area residents Sunday afternoon had arrived at the shelter at Yavapai College near Prescott, located about 30 miles from Yarnell, according to Brian Gomez, spokesman for the Red Cross Grand Canyon Chapter.

He said the power went out at the shelter due to monsoons but was restored.

More people were expected to need shelter as officials ordered still further evacuations, Gomez said. The Red Cross was poised to open a shelter at Wickenburg High School, he said.

Officials opened a shelter for livestock and large animals at Hidden Spring Ranch on Highways 89 in a part of Peeples Valley that as of Sunday was safe from the fire, officials said.

Fueled by chaparral and grass, the blaze was burning uphill on state land about 25 miles north of Wickenburg with 15-to 20-foot flames, he said.

The Yavapai County Sheriff's Office evacuated the Double Bar A Ranch and Model Creek areas, officials said. A reverse 911 call was sent and sheriff's deputies went door-to-door to alert residents.

The temperature warmed to 101 degrees Sunday afternoon and southwest winds were blowing up to 22 miles per hour, Reichling said.

The low humidity, type of fuel, topography and northwest direction of the wind was feeding the and pushing it up the hill toward the communities, Reichling said.

Firefighters were establishing structure protection in the Yarnell area and directly attacking the fire along its eastern flank.

A large animal shelter was set up at the Hidden Springs Ranch on Arizona 89 southwest of Hayes Ranch Road, he said. A shelter for people and small animals is being opened at Yavapai College at 1100 E. Sheldon in Prescott.

Fire crews across the state also were battling three other blazes, including firefighters in Prescott who continue to work to get the Doce Fire fully contained, authorities said.